Effect of oleic acid on insulin secretion by the isolated perfused rat pancreas

Campillo, J. E.; Luyckx, A; Torres, Mauricio; Lefèbvre, Pierre

doi:10.1007/bf01221954

Cited by 40 publications

(16 citation statements)

References 30 publications

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“…Previous studies have shown that fatty acids can stimulate insulin release or potentiate glucose-induced insulin release (17,(30)(31)(32), although the mechanism of stimulation is unknown (18). In mouse islets, palmitate did not stimulate insulin secretion at low glucose concentrations but did enhance release at stimulatory glucose concentrations (18).…”

Section: Fig 4 Lack Of Augmentation By Various Concentrations Of Lamentioning

confidence: 91%

Palmitate and myristate selectively mimic the effect of glucose in augmenting insulin release in the absence of extracellular Ca2+.

Komatsu

Sharp

1998

Diabetes

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Under Ca2+-free conditions, activation of the pancreatic beta-cell with forskolin and 12-O-tetradecanoylphorbol 13-acetate (TPA) is permissive for the augmentation of insulin release by glucose and other nutrients. The ability of fatty acids to mimic the effect of glucose and thereby augment insulin secretion in the absence of extracellular Ca2+ is the focus of the present study. In the absence of extracellular Ca2+, glucose, palmitate, and myristate had no effect on insulin release. When, under Ca2+-free conditions, the islets were treated with forskolin to raise cyclic AMP levels and activate protein kinase A and with TPA to activate protein kinase C, glucose, palmitate, and myristate all augmented release to approximately the same extent. No other saturated fatty acid with chain lengths in the C = 6-22 range augmented the release of insulin. This selective augmentation by palmitate or myristate was not seen with forskolin alone, and was seen slightly with TPA and strongly with the combination of forskolin and TPA. The response, which developed slowly and had a time course similar to that of second-phase insulin release, was abolished by the physiological inhibitor norepinephrine. The results suggest that the mechanism underlying the Ca2+-independent augmentation of insulin release by glucose and other nutrients involves the proposed malonyl-CoA/long-chain acyl-CoA pathway with specificity for myristoyl- and palmitoyl-CoA esters and/or their derivatives.

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Section: Fig 4 Lack Of Augmentation By Various Concentrations Of Lamentioning

confidence: 91%

Palmitate and myristate selectively mimic the effect of glucose in augmenting insulin release in the absence of extracellular Ca2+.

Komatsu

Sharp

1998

Diabetes

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“…Second, in the fed state, this component was not needed for efficient GSIS. In considering what such a "glucose cofactor" might be, our attention turned to free fatty acids for the following reasons: (a) an elevated plasma FFA level is one of the hallmarks of the fasted state; (b) it has long been known that FFA are capable of enhancing GSIS both in vivo (17,(24)(25)(26)(27) and in vitro (9,12,16,(28)(29)(30)(31)(32)(33)(34); and (c) there is growing evidence for an interaction between glucose and fatty acid metabolism as an integral component of stimulus-secretion coupling within the ␤ cell (9-12, 16, 33-36; see below).…”

Section: Discussionmentioning

confidence: 99%

Essentiality of circulating fatty acids for glucose-stimulated insulin secretion in the fasted rat.

Stein¹,

Esser²,

Stevenson³

et al. 1996

J. Clin. Invest.

342

271

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We asked whether the well known starvation-induced impairment of glucose-stimulated insulin secretion (GSIS) seen in isolated rat pancreas preparations also applies in vivo. Accordingly, fed and 18-24-h-fasted rats were subjected to an intravenous glucose challenge followed by a hyperglycemic clamp protocol, during which the plasma-insulin concentration was measured. Surprisingly, the acute (5 min) insulin response was equally robust in the two groups. However, after infusion of the antilipolytic agent, nicotinic acid, to ensure low levels of plasma FFA before the glucose load, GSIS was essentially ablated in fasted rats, but unaffected in fed animals. Maintenance of a high plasma FFA concentration by coadministration of Intralipid plus heparin to nicotinic acid-treated rats (fed or fasted), or further elevation of the endogenous FFA level in nonnicotinic acidtreated fasted animals by infusion of etomoxir (to block hepatic fatty acid oxidation), resulted in supranormal GSIS. The in vivo findings were reproduced in studies with the perfused pancreas from fed and fasted rats in which GSIS was examined in the absence and presence of palmitate. The results establish that in the rat, the high circulating concentration of FFA that accompanies food deprivation is a sine qua non for efficient GSIS when a fast is terminated. They also serve to underscore the powerful interaction between glucose and fatty acids in normal ␤ cell function and raise the possibility that imbalances between the two fuels in vivo could have pathological consequences. ( J. Clin. Invest. 1996. 97:2728-2735.)

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“…Fatty acids are required for glucose-stimulated insulin secretion in some systems (31). In islets and rodents, short term exposure to elevated fatty acid concentrations enhances glucose-stimulated insulin secretion (32)(33)(34). Long term exposure decreases glucose-stimulated insulin secretion (35,36).…”

Section: Fig 7 Lpl Is Located In Insulin-expressing Cells In Pancrementioning

confidence: 99%

Glucose and Insulin Stimulate Heparin-releasable Lipoprotein Lipase Activity in Mouse Islets and INS-1 Cells

Cruz¹,

Kwon²,

Marshall³

et al. 2001

Journal of Biological Chemistry

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Lipoprotein lipase (LpL) provides tissues with triglyceride-derived fatty acids. Fatty acids affect ␤-cell function, and LpL overexpression decreases insulin secretion in cell lines, but whether LpL is regulated in ␤-cells is unknown. To test the hypothesis that glucose and insulin regulate LpL activity in ␤-cells, we studied pancreatic islets and INS-1 cells. Acute exposure of ␤-cells to physiological concentrations of glucose stimulated both total cellular LpL activity and heparin-releasable LpL activity. Glucose had no effect on total LpL protein mass but instead promoted the appearance of LpL protein in a heparin-releasable fraction, suggesting that glucose stimulates the translocation of LpL from intracellular to extracellular sites in ␤-cells. The induction of heparinreleasable LpL activity was unaffected by treatment with diazoxide, an inhibitor of insulin exocytosis that does not alter glucose metabolism but was blocked by conditions that inhibit glucose metabolism. In vitro hyperinsulinemia had no effect on LpL activity in the presence of low concentrations of glucose but increased LpL activity in the presence of 20 mM glucose. Using dual-laser confocal microscopy, we detected intracellular LpL in vesicles distinct from those containing insulin. LpL was also detected at the cell surface and was displaced from this site by heparin in dispersed islets and INS-1 cells. These results show that glucose metabolism controls the trafficking of LpL activity in ␤-cells independent of insulin secretion. They suggest that hyperglycemia and hyperinsulinemia associated with insulin resistance may contribute to progressive ␤-cell dysfunction by increasing LpL-mediated delivery of lipid to islets.

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Effect of oleic acid on insulin secretion by the isolated perfused rat pancreas

Cited by 40 publications

References 30 publications

Palmitate and myristate selectively mimic the effect of glucose in augmenting insulin release in the absence of extracellular Ca2+.

Palmitate and myristate selectively mimic the effect of glucose in augmenting insulin release in the absence of extracellular Ca2+.

Essentiality of circulating fatty acids for glucose-stimulated insulin secretion in the fasted rat.

Glucose and Insulin Stimulate Heparin-releasable Lipoprotein Lipase Activity in Mouse Islets and INS-1 Cells

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